In modern computers, SRAM is often used as cache memory for the CPU.
DRAM stores a bit of data using a transistor and capacitor pair, which together comprise a DRAM cell.
Developed at the University of Manchester in England, the Williams tube provided the medium on which the first electronically stored-memory program was implemented in the Manchester Small-Scale Experimental Machine (SSEM) computer, which first successfully ran a program on 21 June 1948.
RAM contains multiplexing and demultiplexing circuitry, to connect the data lines to the addressed storage for reading or writing the entry.
Dynamic random-access memory (DRAM) allowed replacement of a 4 or 6-transistor latch circuit by a single transistor for each memory bit, greatly increasing memory density at the cost of volatility.